From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 18 Jul 2011 13:59:17 +0200
Subject: softirq: Disable softirq stacks for RT
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 720032a2dc7f383d0d343d7232a23e3046d3b84c
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension
Disable extra stacks for softirqs. We want to preempt softirqs and
having them on special IRQ-stack does not make this easier.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
arch/powerpc/kernel/irq.c | 2 ++
arch/powerpc/kernel/misc_32.S | 2 ++
arch/powerpc/kernel/misc_64.S | 2 ++
arch/sh/kernel/irq.c | 2 ++
arch/sparc/kernel/irq_64.c | 2 ++
arch/x86/entry/entry_64.S | 2 ++
arch/x86/kernel/irq_32.c | 2 ++
include/linux/interrupt.h | 2 +-
8 files changed, 15 insertions(+), 1 deletion(-)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -705,6 +705,7 @@ void irq_ctx_init(void)
}
}
+#ifndef CONFIG_PREEMPT_RT_FULL
void do_softirq_own_stack(void)
{
struct thread_info *curtp, *irqtp;
@@ -722,6 +723,7 @@ void do_softirq_own_stack(void)
if (irqtp->flags)
set_bits(irqtp->flags, &curtp->flags);
}
+#endif
irq_hw_number_t virq_to_hw(unsigned int virq)
{
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -41,6 +41,7 @@
* We store the saved ksp_limit in the unused part
* of the STACK_FRAME_OVERHEAD
*/
+#ifndef CONFIG_PREEMPT_RT_FULL
_GLOBAL(call_do_softirq)
mflr r0
stw r0,4(r1)
@@ -57,6 +58,7 @@ _GLOBAL(call_do_softirq)
stw r10,THREAD+KSP_LIMIT(r2)
mtlr r0
blr
+#endif
/*
* void call_do_irq(struct pt_regs *regs, struct thread_info *irqtp);
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -31,6 +31,7 @@
.text
+#ifndef CONFIG_PREEMPT_RT_FULL
_GLOBAL(call_do_softirq)
mflr r0
std r0,16(r1)
@@ -41,6 +42,7 @@ _GLOBAL(call_do_softirq)
ld r0,16(r1)
mtlr r0
blr
+#endif
_GLOBAL(call_do_irq)
mflr r0
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -147,6 +147,7 @@ void irq_ctx_exit(int cpu)
hardirq_ctx[cpu] = NULL;
}
+#ifndef CONFIG_PREEMPT_RT_FULL
void do_softirq_own_stack(void)
{
struct thread_info *curctx;
@@ -174,6 +175,7 @@ void do_softirq_own_stack(void)
"r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
);
}
+#endif
#else
static inline void handle_one_irq(unsigned int irq)
{
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -854,6 +854,7 @@ void __irq_entry handler_irq(int pil, st
set_irq_regs(old_regs);
}
+#ifndef CONFIG_PREEMPT_RT_FULL
void do_softirq_own_stack(void)
{
void *orig_sp, *sp = softirq_stack[smp_processor_id()];
@@ -868,6 +869,7 @@ void do_softirq_own_stack(void)
__asm__ __volatile__("mov %0, %%sp"
: : "r" (orig_sp));
}
+#endif
#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(void)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1127,6 +1127,7 @@ EXPORT_SYMBOL(native_load_gs_index)
jmp 2b
.previous
+#ifndef CONFIG_PREEMPT_RT_FULL
/* Call softirq on interrupt stack. Interrupts are off. */
ENTRY(do_softirq_own_stack)
pushq %rbp
@@ -1137,6 +1138,7 @@ ENTRY(do_softirq_own_stack)
leaveq
ret
ENDPROC(do_softirq_own_stack)
+#endif
#ifdef CONFIG_XEN
idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -127,6 +127,7 @@ void irq_ctx_init(int cpu)
cpu, per_cpu(hardirq_stack, cpu), per_cpu(softirq_stack, cpu));
}
+#ifndef CONFIG_PREEMPT_RT_FULL
void do_softirq_own_stack(void)
{
struct irq_stack *irqstk;
@@ -143,6 +144,7 @@ void do_softirq_own_stack(void)
call_on_stack(__do_softirq, isp);
}
+#endif
bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
{
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -484,7 +484,7 @@ struct softirq_action
asmlinkage void do_softirq(void);
asmlinkage void __do_softirq(void);
-#ifdef __ARCH_HAS_DO_SOFTIRQ
+#if defined(__ARCH_HAS_DO_SOFTIRQ) && !defined(CONFIG_PREEMPT_RT_FULL)
void do_softirq_own_stack(void);
#else
static inline void do_softirq_own_stack(void)